Thank you all for interesting and informative responses. After looking up several of your proposed ideas, and discussing them with co-workers, we've come up with another scheme. Brainstorming leads to interesting ideas.
We're looking into "simply" building a Faraday Cage around the vehicle...
I've searched the Internet for many weeks and have also looked at all 49 threads on this site to no avail. I work for a state government agency that is concerned about potential effects of nuclear electromagnetic pulses (EMP) and solar coronal mass ejections (CME). The concerns are based on...